CN109193584B - A kind of current protection method of the power distribution network containing distributed photovoltaic power - Google Patents
A kind of current protection method of the power distribution network containing distributed photovoltaic power Download PDFInfo
- Publication number
- CN109193584B CN109193584B CN201811130061.4A CN201811130061A CN109193584B CN 109193584 B CN109193584 B CN 109193584B CN 201811130061 A CN201811130061 A CN 201811130061A CN 109193584 B CN109193584 B CN 109193584B
- Authority
- CN
- China
- Prior art keywords
- fault
- current protection
- protection device
- self
- adaptive
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
- 238000000034 method Methods 0.000 title claims abstract description 21
- 230000003044 adaptive effect Effects 0.000 claims abstract description 27
- 238000009434 installation Methods 0.000 claims description 17
- 230000001934 delay Effects 0.000 claims description 7
- 238000011144 upstream manufacturing Methods 0.000 claims description 4
- 238000004364 calculation method Methods 0.000 claims description 3
- 230000001681 protective effect Effects 0.000 abstract description 5
- 238000004088 simulation Methods 0.000 description 5
- 238000010248 power generation Methods 0.000 description 4
- 230000005540 biological transmission Effects 0.000 description 3
- 238000004891 communication Methods 0.000 description 2
- 238000010586 diagram Methods 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 238000013016 damping Methods 0.000 description 1
- 239000000284 extract Substances 0.000 description 1
- 239000002803 fossil fuel Substances 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 230000007935 neutral effect Effects 0.000 description 1
- 230000008092 positive effect Effects 0.000 description 1
- 230000001360 synchronised effect Effects 0.000 description 1
Classifications
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
- H02H7/00—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions
- H02H7/26—Sectionalised protection of cable or line systems, e.g. for disconnecting a section on which a short-circuit, earth fault, or arc discharge has occured
Landscapes
- Supply And Distribution Of Alternating Current (AREA)
Abstract
The present invention provides a kind of current protection method of power distribution network containing distributed photovoltaic power, including longitudinal differential current protective device is arranged for photovoltaic access point higher level's route and system power supply side configures I, II, III three-stage adaptive Current Protection device；After power distribution network breaks down, adaptive Current Protection device first determines whether that fault type is line to line fault or three-phase shortcircuit and accordingly determines fault type COEFFICIENT Kd；Adaptive Current Protection device judges two-phase or three-phase fault and the impedance of protective device back side and back side equivalent source electromotive force；Setting valve is acted in line computation I, II, III three section protection and makes corresponding protection act and each longitudinal differential current protective device judges fault direction respectively and makes corresponding protection act.Guard method of the invention is not influenced by system operation mode, can ensure that each protective device correctly acts, and functional reliability is high.
Description
The invention relates to a divisional application of an invention patent application with the application number of 201610997679.5 and the application date of 2016, 11 and 14 and named as a current protection method for a power distribution network containing a distributed photovoltaic power supply.
Technical Field
The invention relates to a protection method for a power distribution network, in particular to a current protection method suitable for the power distribution network containing distributed photovoltaic power sources.
Background
Although the grid connection of the distributed photovoltaic power supply can improve the stability of the system and reduce the use of fossil fuels, the existing protection is influenced to a certain extent, so that the traditional current protection in the power distribution network is subjected to misoperation or refusal, and therefore, the research on the protection of the power distribution network with the distributed photovoltaic power supply access gradually becomes a hot problem of domestic and foreign research.
The photovoltaic grid-connected power generation is developed quickly, a traditional single-power radial distribution network is changed into a multi-power distribution network along with the access of a large number of distributed photovoltaic power supplies, and when the distribution network breaks down, the size and the direction of short-circuit current of the distribution network can be changed greatly, so that a current protection mode adopted by the traditional distribution network is influenced greatly, and the current protection device in the traditional distribution network is subjected to false operation or refusal operation; for the protection of the downstream of the distributed power supply access point, the current flowing through the current protection device can be increased due to the boosting effect of the photovoltaic power supply, so that the protection range of the current protection device is increased, and the protection range can extend to the next line, so that the current protection device is subjected to misoperation. Meanwhile, the photovoltaic power generation system is not provided with a rotating part, so that the photovoltaic power generation system is free of damping effect caused by inertia, the fault characteristics of the photovoltaic power generation system are different from those of a traditional synchronous motor, the output of a photovoltaic power supply in the fault period is generally symmetrical three-phase current, the capacity of the photovoltaic power supply is much smaller than that of the system, and the current protection device in the traditional power distribution network cannot act correctly after being connected into the distributed photovoltaic power supply due to the weak power supply characteristics. Therefore, it is necessary to research and provide a new more reasonable current protection method for the technical problem of current protection of the power distribution network containing the distributed photovoltaic power supply.
Disclosure of Invention
The purpose of the invention is: aiming at the problems in the prior art, the current protection method for the power distribution network with the distributed photovoltaic power supply is provided, the method can not be influenced by the system operation mode, and the current protection device can be ensured to correctly act when a fault occurs.
The technical scheme of the invention is as follows: the invention discloses a current protection method for a power distribution network containing a distributed photovoltaic power supply, which comprises the following steps:
respectively arranging 1 longitudinal differential current protection device at two ends of a last-stage circuit of a photovoltaic power supply access point, and additionally arranging circuit breakers at the last-stage circuit and the photovoltaic side of the next-last-stage circuit of the last-stage circuit; configuring I, II and III three-section type self-adaptive current protection devices on other lines of a system power supply side;
secondly, after the power distribution network fails, the self-adaptive current protection device firstly judges whether the fault type is a two-phase short circuit or a three-phase short circuit and correspondingly determines a fault type coefficient Kd；
Thirdly, the self-adaptive current protection device adopts the formula (1) to calculate the back side impedance Z of the self-adaptive current protection device when the two-phase short circuit fault occurss(ii) a Self-adaptive current protection device back side impedance Z in real-time calculation of three-phase short-circuit fault by adopting formula (2)s：
In the formula,is a negative sequence fault voltage at the installation of the adaptive current protection device;is a negative sequence fault current at the installation of the adaptive current protection device;
in the formula,positive sequence fault component power for adaptive current protection device installationPressing;is a positive sequence fault component current at the installation of the adaptive current protection device;
fourthly, the self-adaptive current protection device adopts the formula (3) to calculate the back side equivalent power source electromotive force
In the formula,the self-adaptive current protection device respectively acquires the fault phase voltage and the fault phase current at the protection device during the fault,is phase A, phase B or phase C;
the self-adaptive current protection device calculates the setting values of the three protection actions of I, II and III on line and makes corresponding protection actions:
the self-adaptive current protection device adopts a formula (4) to calculate the I-section protection action setting value I on lineI Z：
In the formula: kkThe value is 1.1-1.3 for the reliability coefficient; kdDetermining the fault type coefficient in the step two; esProtecting the back equivalent power electromotive force obtained in the step (iv); zsProtecting the back side impedance obtained in the step (c); zLIs the impedance of the protected line of section I;
if the fault current flowing through the self-adaptive current protection device is larger than the calculated I-section protection action setting value II ZThen the outlet relay of the self-adaptive current protection device is instantaneously connectedSending a tripping signal to a circuit breaker controlled by the self-adaptive current protection device to trip the circuit breaker;
the self-adaptive current protection device adopts the formula (5) to calculate the II-section protection action setting value I on lineII Z：
In the formula,the value is 1.1-1.3 for the reliability coefficient; kdDetermining the fault type coefficient in the step two; esProtecting the back equivalent power electromotive force obtained in the step (iv); zsObtaining the back side impedance of the self-adaptive current protection device; zL bookIs the impedance of the line in the current section; zUnder LTo protect the next stage of line impedance;
if the fault current flowing through the self-adaptive current protection device is larger than the calculated II-section protection action setting value III ZIf the fault occurs, the outlet relay of the self-adaptive current protection device delays for 0.5s to act, and sends a tripping signal to a circuit breaker controlled by the self-adaptive current protection device to trip the circuit breaker;
the self-adaptive current protection device adopts the formula (6) to calculate the III-section protection action setting value on line
In the formula,the value is 1.1-1.3 for the reliability coefficient; kssThe value is 1.2-1.3 for the self-starting coefficient; kreThe value is 0.85 for the return coefficient; i isloadIs the real-time load current flowing through the adaptive current protection device;
if the fault current flowing through the self-adaptive current protection device is larger than the calculated self-adaptive current III section protection action setting valueThe outlet relay of the self-adaptive current protection device delays 0.5 second action compared with the next self-adaptive section III after the fault, and sends a tripping signal to a circuit breaker controlled by the self-adaptive current protection device to trip the circuit breaker; if the next stage is not provided with the self-adaptive section III, delaying the action for 1 second after the fault of the relay at the outlet of the self-adaptive current protection device, and sending a tripping signal to a circuit breaker controlled by the self-adaptive current protection device to trip the circuit breaker;
judging the fault direction and communicating and exchanging the judgment results by the longitudinal differential current protection devices arranged at two ends of the upper-stage line of the photovoltaic access point respectively;
if the 2 longitudinal differential current protection devices simultaneously judge that the fault is a positive direction fault, executing the step (c); if the judgment result of the longitudinal differential current protection device positioned on the system power supply side in the 2 longitudinal differential current protection devices is a reverse direction fault, executing the step ((b)); if the longitudinal differential current protection device positioned on the photovoltaic power supply side in the 2 longitudinal differential current protection devices judges that the fault is a fault in the opposite direction, executing a step ninthly;
seventhly, the 2 longitudinal differential current protection devices control circuit breakers arranged on two sides of a last-stage line of the photovoltaic access point to trip without time delay, and faults are isolated;
eighthly, 2 pilot differential current protection devices judge an upstream line of a previous-stage line with a fault positioned at the photovoltaic access point, 2 pilot direction protection devices lock circuit breakers at two sides of the previous-stage line of the photovoltaic access point, and meanwhile, a corresponding self-adaptive current protection device at the system power supply side controls to jump off the circuit breaker close to the photovoltaic side under the control of the self-adaptive current protection device to cut off the current of the photovoltaic power supply;
the ninthly 2 longitudinal differential current protection devices lock circuit breakers on two sides of a previous-stage line of the photovoltaic access point, and the self-adaptive current protection device in a next previous-stage line of the photovoltaic access point controls the circuit breaker close to the photovoltaic side to be controlled not to trip;
in the second step, the self-adaptive current protection device judges the fault type and determines the fault type coefficient KdThe method comprises the following steps:
system side A phase current acquired after fault by self-adaptive current protection deviceAnd C phase currentAnd the judgment is carried out according to the following rules:
if it isJudging the short circuit of the BC two phases;
if it isDetermining that the AB two phases are short-circuited;
if it isJudging that the AC two phases are short-circuited;
if the first three formulas are not met, judging a three-phase fault;
wherein K1The value is 0.5; if two-phase fault is determined, the fault type coefficient KdValue takingIf three-phase fault is determined, the fault type coefficient KdTaking a value of 1;
in the step III, the negative sequence fault voltage in the formula (1)And negative sequence fault currentAnd positive sequence fault component voltage in equation (2)And positive sequence fault component currentFrom:
the self-adaptive current protection device acquires a power frequency fault voltage component delta u and a power frequency fault current component delta i after a fault occurs; wherein,
the voltage u of the installation position of the self-adaptive current protection device is measured according to the power frequency fault voltage component delta umSubtracting the voltage u in the pre-fault state[0]And then obtaining;
the power frequency fault current component Delta i is measured by the current i at the installation position of the self-adaptive current protection devicemSubtracting the current i in the pre-fault state[0]And obtaining the product.
The invention has the positive effects that: (1) the invention provides a new method for current protection of a power distribution network containing a distributed photovoltaic power supply, the protection method is not influenced by a system operation mode, a setting value of protection can be calculated on line, and is irrelevant to the size of the photovoltaic power supply access capacity and the size of a load, when the load and the photovoltaic power supply access capacity are changed, the protection can act correctly, the reliability is higher, and the protection range is larger; communication equipment is only installed at two ends of a power transmission line accessed by a photovoltaic power supply, so that dependence on the communication equipment is reduced; meanwhile, because the traditional power distribution network is a radial network of a single power supply, a current protection device is generally only arranged on the system side, the current protection devices are arranged at two ends of a power transmission line accessed by a photovoltaic power supply on the basis of the traditional power distribution network protection, and the current protection devices are only arranged on the system side of the other power transmission lines.
Drawings
Fig. 1 is a schematic diagram of a simulation model of a power distribution network including a distributed photovoltaic power supply used in an embodiment, and the diagram also schematically shows a setting scheme of a current protection device used in the current protection method of the present invention.
Detailed Description
The present invention will be described in further detail with reference to the accompanying drawings and specific embodiments.
(example 1)
The current protection method for the power distribution network with the distributed photovoltaic power supply comprises the following steps:
firstly, respectively arranging 1 longitudinal differential current protection device at two ends of a last-stage circuit of a photovoltaic power supply access point, and additionally arranging circuit breakers at the last-stage circuit and the photovoltaic side of the next-last-stage circuit of the last-stage circuit; the other lines of the power distribution network are all provided with self-adaptive current protection devices of I, II and III sections at the power supply side of the system.
The last-stage line and the next-last-stage line refer to lines close to and closer to the system power supply.
Secondly, after the system has a fault, the self-adaptive current protection device firstly judges whether the fault type is a two-phase short circuit or a three-phase short circuit so as to determine a corresponding fault type coefficient Kd：
System side A phase current acquired after fault by self-adaptive current protection deviceAnd C phase currentAnd the judgment is carried out according to the following rules:
if it isJudging the short circuit of the BC two phases; if it isDetermining that the AB two phases are short-circuited; if it isJudging that the AC two phases are short-circuited; if the first three formulas are not satisfied, judging three phasesA failure;
wherein K1The value is 0.5; if two-phase fault is determined, the fault type coefficient KdValue takingFault type coefficient K if three-phase fault occursdTaking the value 1.
Thirdly, the self-adaptive current protection device utilizes the power frequency fault voltage component delta u and the power frequency fault current component delta i to calculate the back side impedance Z of the protection device in real timesThe power frequency fault component voltage delta u and the power frequency fault component current delta i are defined as the voltage u measured at the installation position of the protection device when the power system has a faultmCurrent imSubtracting the voltage u in the pre-fault state[0]Current i[0]The resulting voltage, current magnitude; . In a power distribution network with ungrounded neutral point, the power frequency fault component voltage delta u is composed of positive sequence component voltageAnd negative sequence component voltageAnd (4) forming. The power frequency fault component current Delta i is composed of positive sequence component currentWith negative sequence component currentIs composed of, i.e.
When two phases are short-circuited, the self-adaptive current protection device utilizes a built-in negative sequence current extractor to extract negative sequence component voltage and current in power frequency fault voltage and current components to calculate the back side impedance of the protection device:
in the formula,is a negative sequence fault voltage at the installation of the adaptive current protection device;is the negative sequence fault current at the installation of the adaptive current protection device.
When a three-phase fault occurs, the change of the output current of the photovoltaic power supply before and after the fault is ignored, the self-adaptive current protection device extracts the positive sequence fault component voltage and the positive sequence fault component current in the power frequency fault voltage and current component by using the built-in positive sequence current extractor, and calculates the back side impedance Z of the protection devices：
In the formula,is a positive sequence fault component voltage at the installation of the adaptive current protection device;is a positive sequence fault component current at the installation of the adaptive current protection device.
Fourthly, calculating the equivalent power electromotive force at the back side of the self-adaptive current protection device
In the formula,the fault phase voltage and the fault phase current at the protection device during the fault are respectively.Refers to phase A, phase B or phase C.
Fifthly, calculating the protection action setting value of the self-adaptive current protection device on line, and self-adapting the I-section setting value II ZComprises the following steps:
in the formula: kkThe value is 1.1-1.3 for the reliability coefficient; kdDetermining the fault type coefficient in the step two; esProtecting the back equivalent power electromotive force obtained in the step (iv); zsObtaining the back side impedance of the self-adaptive current protection device; zLIs the protected line impedance. If the fault current flowing through the protection device is larger than the setting value of the section I of the self-adaptive current, an outlet relay of the self-adaptive current protection device instantly sends a tripping signal to a circuit breaker controlled by the self-adaptive current protection device to trip the circuit breaker.
The self-adaptive II section setting value is as follows:
in the formula,the value is 1.1-1.3 for the reliability coefficient; kdDetermining the fault type coefficient in the step two; esProtecting the back equivalent power electromotive force obtained in the step (iv); zsProtecting the back side impedance obtained in the step (c); zL bookIs the impedance of the line in the current section; zUnder LTo protect the next stage of line impedance. If the fault current flowing through the protection device is larger than the self-adaptive current II section protection action setting value, the outlet relay of the self-adaptive current protection device delays for 0.5s to act after the fault, and sends a tripping signal to the circuit breaker controlled by the self-adaptive current protection device to trip the circuit breaker.
The self-adaptive III-section setting value is as follows:
in the formula,the value is 1.1-1.3 for the reliability coefficient; kssThe value is 1.2-1.3 for the self-starting coefficient; kreThe value is 0.85 for the return coefficient; i isloadFor the real-time load current flowing through the protection, if the fault current flowing through the protection device is larger than the self-adaptive current III section protection action setting valueThe outlet relay of the self-adaptive current protection device delays 0.5 second action compared with the next self-adaptive section III after the fault, and sends a tripping signal to a circuit breaker controlled by the self-adaptive current protection device to trip the circuit breaker; if the next stage is not provided with the self-adaptive section III, the outlet relay of the self-adaptive current protection device delays for 1 second to act after the fault, and sends a tripping signal to a circuit breaker controlled by the self-adaptive current protection device to trip the circuit breaker; .
Judging the fault direction and communicating and exchanging the judgment results by the longitudinal differential current protection devices arranged at two ends of the upper-stage line of the photovoltaic access point respectively;
if the 2 longitudinal differential current protection devices simultaneously judge that the fault is a positive direction fault, executing the step (c); if the judgment result of the longitudinal differential current protection device positioned on the system power supply side in the 2 longitudinal differential current protection devices is a reverse direction fault, executing the step ((b)); and ninthly, if the longitudinal differential current protection device positioned on the photovoltaic power supply side in the 2 longitudinal differential current protection devices judges that the fault is a fault in the opposite direction, executing step ninthly.
And seventhly, the 2 longitudinal differential current protection devices control circuit breakers arranged on two sides of the upper-stage line of the photovoltaic access point to trip without time delay so as to isolate faults.
And eighthly, judging an upstream line of a previous-stage line with a fault in the photovoltaic access point by the 2 pilot differential current protection devices, locking circuit breakers at two sides of the previous-stage line of the photovoltaic access point by the 2 pilot direction protection devices, and simultaneously controlling to open circuit breakers close to the photovoltaic side and controlled by the self-adaptive current protection device at the power supply side of the system to cut off the current of the photovoltaic power supply.
And ninthly, the ninthly 2 longitudinal differential current protection devices lock circuit breakers on two sides of the last-stage circuit of the photovoltaic access point, and the self-adaptive current protection device in the next-last-stage circuit of the photovoltaic access point controls the circuit breaker close to the photovoltaic side to which the self-adaptive current protection device belongs not to trip.
In the above steps, the longitudinal differential current protection device determines the fault direction and uses the built-in direction element to determine.
The direction component determines the direction of the fault, take phase A as an example, if
The positive direction fault is determined.
In the formula,to protect the BC line voltage at the installation during a fault;taking the value of 60 o;the direction is determined as prior art for phase a current flowing through the protection device during a fault and will not be described in detail.
In order to verify the effectiveness of the current protection method for the power distribution network with the distributed photovoltaic power supply of this embodiment, the present embodiment adopts a schematic simulation model of the power distribution network with the distributed photovoltaic power supply as shown in fig. 1, and further details are provided for the present invention.
As shown in figure 1, directional pilot protection 3 and 5 are arranged at two ends of a previous-stage line CD of a photovoltaic access point bus D, a breaker BRK is additionally arranged on the photovoltaic side of a previous-stage line BC of the previous-stage line, and when a directional element is judged in protection 3When a fault occurs in the reverse direction, the BRK trips to cut off the short circuit current provided by the photovoltaic. The other line system sides are all provided with I, II and III three-section type self-adaptive current protection 1, 2 and 4, Z in figure 1L1To ZL4Is the impedance of the corresponding line.
The relevant simulation parameters of the distribution network with distributed photovoltaic power sources shown in fig. 1 are shown in table 1.
TABLE 1 simulation parameters
Suppose that when a two-phase short circuit occurs on the line CD, the position of the fault point f on the line BC is changed (the distance between the fault point and the protection 5 is represented by alpha, which is the proportion of the length of the line CD), and the back side impedances Z of the protection 1 and 2 are respectively adaptedsBack electromotive force EsTable 2 shows the I-stage setting values and the operation conditions. The results of the longitudinal protection 3 and 5 direction judgment, the action condition and whether the BRK trips are shown in Table 3.
TABLE 2 adaptive Current interruption protection 1, 2I section setting value and action condition
TABLE 3 longitudinal protection 3, 5 direction judgment result and action condition, whether BRK is tripped or not
Secondly, assuming that when a two-phase BC short circuit occurs on the line BC, the back side impedance, back side equivalent power electromotive force, I-section setting value and action condition of the adaptive current protection 1 and 2 are shown in Table 4. The results of the longitudinal protection 3 and 5 direction judgment, the action condition and whether the BRK trips are shown in Table 5.
TABLE 4 adaptive Current interruption protection 1, 2I section setting value and action condition
TABLE 5 longitudinal protection 3, 5 direction judgment result and action condition, whether BRK is tripped or not
Thirdly, supposing that ABC three-phase short circuit occurs on the line CD, changing the position of the fault point f (the distance between the fault point and the protection 5 is represented by alpha to account for the length of the line CD), and the back side impedance, back side equivalent power electromotive force, I section setting value, action condition and whether BRK is tripped or not of the adaptive current protection 1 and 2 are shown in the table 6.
TABLE 6 adaptive Current interruption protection 1, 2I segment setting value and action condition, BRK trip or not
It is assumed that a three-phase short circuit occurs in the line BC, and the back-side impedance, back-side equivalent power electromotive force, I-stage setting value, and operation condition of the adaptive current protection 1, 2 are shown in table 7.
TABLE 7 adaptive Current interruption protection 1, 2I segment setting value and action condition, BRK trip or not
Simulation results show that the protection configuration method can quickly judge the fault section after the fault. When a fault occurs on a line AC, the system side fault current is cut off by the adaptive current protection 1 and 2, and the photovoltaic side fault current is cut off by the protection 3 back side breaker BRK; when the fault occurs in the line CD, the fault is cut off by the pilot protection 3 and 5, and the BRK does not act; when a fault occurs in the line downstream of the bus D, the fault is cut off by the adaptive current protection 4. The protective action is substantially unaffected by the photovoltaic access. And faults at all positions of the feeder line can be quickly cut off. Therefore, the protection configuration method has strong practicability.
The above embodiments are illustrative of specific embodiments of the present invention, and are not restrictive of the present invention, and those skilled in the relevant art can make various changes and modifications without departing from the spirit and scope of the present invention to obtain corresponding equivalent technical solutions, and therefore all equivalent technical solutions should be included in the scope of the present invention.
Claims (1)
1. A current protection method for a power distribution network containing a distributed photovoltaic power supply is characterized by comprising the following steps:
respectively arranging 1 longitudinal differential current protection device at two ends of a last-stage circuit of a photovoltaic power supply access point, and additionally arranging circuit breakers at the last-stage circuit and the photovoltaic side of the next-last-stage circuit of the last-stage circuit; configuring I, II and III three-section type self-adaptive current protection devices on other lines of a system power supply side;
secondly, after the power distribution network fails, the self-adaptive current protection device firstly judges whether the fault type is a two-phase short circuit or a three-phase short circuit and correspondingly determines a fault type coefficient Kd；
Thirdly, the self-adaptive current protection device adopts the formula (1) to calculate the back side impedance Z of the self-adaptive current protection device when the two-phase short circuit fault occurss(ii) a Self-adaptive current protection device back side impedance Z in real-time calculation of three-phase short-circuit fault by adopting formula (2)s：
In the formula,for negative sequence at the installation of the adaptive current protection meansA fault voltage;is a negative sequence fault current at the installation of the adaptive current protection device;
in the formula,is a positive sequence fault component voltage at the installation of the adaptive current protection device;is a positive sequence fault component current at the installation of the adaptive current protection device;
fourthly, the self-adaptive current protection device adopts the formula (3) to calculate the back side equivalent power source electromotive force
In the formula,the self-adaptive current protection device respectively acquires the fault phase voltage and the fault phase current at the protection device during the fault,is phase A, phase B or phase C;
the self-adaptive current protection device calculates the setting values of the three protection actions of I, II and III on line and makes corresponding protection actions:
the self-adaptive current protection device adopts a formula (4) to calculate the I-section protection action setting value I on lineI Z：
In the formula: kkThe value is 1.1-1.3 for the reliability coefficient; kdDetermining the fault type coefficient in the step two; esProtecting the back equivalent power electromotive force obtained in the step (iv); zsObtaining the back side impedance of the self-adaptive current protection device; zLIs the impedance of the protected line of section I;
if the fault current flowing through the self-adaptive current protection device is larger than the calculated I-section protection action setting value II ZIf the current is in the normal state, the outlet relay of the self-adaptive current protection device instantly sends a tripping signal to a circuit breaker controlled by the self-adaptive current protection device to trip the circuit breaker;
the self-adaptive current protection device adopts the formula (5) to calculate the II-section protection action setting value I on lineII Z：
In the formula,the value is 1.1-1.3 for the reliability coefficient; kdDetermining the fault type coefficient in the step two; esProtecting the back equivalent power electromotive force obtained in the step (iv); zsObtaining the back side impedance of the self-adaptive current protection device; zL bookIs the impedance of the line in the current section; zUnder LTo protect the next stage of line impedance;
if the fault current flowing through the self-adaptive current protection device is larger than the calculated II-section protection action setting value III ZIf the fault occurs, the outlet relay of the self-adaptive current protection device delays for 0.5s to act, and sends a tripping signal to a circuit breaker controlled by the self-adaptive current protection device to trip the circuit breaker;
the adaptive current protection device adopts the formula (6)) On-line calculation of III-section protection action setting value
In the formula,the value is 1.1-1.3 for the reliability coefficient; kssThe value is 1.2-1.3 for the self-starting coefficient; kreThe value is 0.85 for the return coefficient; i isloadIs the real-time load current flowing through the adaptive current protection device;
if the fault current flowing through the self-adaptive current protection device is larger than the calculated self-adaptive current III section protection action setting valueThe outlet relay of the self-adaptive current protection device delays 0.5 second action compared with the next self-adaptive section III after the fault, and sends a tripping signal to a circuit breaker controlled by the self-adaptive current protection device to trip the circuit breaker; if the next stage is not provided with the self-adaptive section III, delaying the action for 1 second after the fault of the relay at the outlet of the self-adaptive current protection device, and sending a tripping signal to a circuit breaker controlled by the self-adaptive current protection device to trip the circuit breaker;
judging the fault direction and communicating and exchanging the judgment results by the longitudinal differential current protection devices arranged at two ends of the upper-stage line of the photovoltaic access point respectively;
if the 2 longitudinal differential current protection devices simultaneously judge that the fault is a positive direction fault, executing the step (c); if the judgment result of the longitudinal differential current protection device positioned on the system power supply side in the 2 longitudinal differential current protection devices is a reverse direction fault, executing the step ((b)); if the longitudinal differential current protection device positioned on the photovoltaic power supply side in the 2 longitudinal differential current protection devices judges that the fault is a fault in the opposite direction, executing a step ninthly;
seventhly, the 2 longitudinal differential current protection devices control circuit breakers arranged on two sides of a last-stage line of the photovoltaic access point to trip without time delay, and faults are isolated;
eighthly, 2 pilot differential current protection devices judge an upstream line of a previous-stage line with a fault positioned at the photovoltaic access point, 2 pilot direction protection devices lock circuit breakers at two sides of the previous-stage line of the photovoltaic access point, and meanwhile, a corresponding self-adaptive current protection device at the system power supply side of the upstream line of the previous-stage line of the photovoltaic access point controls to jump off the circuit breaker close to the photovoltaic side and controlled by the self-adaptive current protection device to cut off the current of the photovoltaic power supply;
the ninthly 2 longitudinal differential current protection devices lock circuit breakers on two sides of a previous-stage line of the photovoltaic access point, and the self-adaptive current protection device in a next previous-stage line of the photovoltaic access point controls the circuit breaker close to the photovoltaic side to be controlled not to trip;
in the second step, the self-adaptive current protection device judges the fault type and determines the fault type coefficient KdThe method comprises the following steps:
system side A phase current acquired after fault by self-adaptive current protection deviceAnd C phase currentAnd the judgment is carried out according to the following rules:
if it isJudging the short circuit of the BC two phases;
if it isDetermining that the AB two phases are short-circuited;
if it isThen determine AC twoPhase short circuit;
if the first three formulas are not met, judging a three-phase fault;
wherein K1The value is 0.5; if two-phase fault is determined, the fault type coefficient KdValue takingIf three-phase fault is determined, the fault type coefficient KdTaking a value of 1;
in the third step, the negative sequence fault voltage in the formula (1)And negative sequence fault currentAnd positive sequence fault component voltage in equation (2)And positive sequence fault component currentFrom:
the self-adaptive current protection device acquires a power frequency fault voltage component delta u and a power frequency fault current component delta i after a fault occurs; wherein,
the voltage u of the installation position of the self-adaptive current protection device is measured according to the power frequency fault voltage component delta umSubtracting the voltage u in the pre-fault state[0]And then obtaining;
the power frequency fault current component Delta i is measured by the current i at the installation position of the self-adaptive current protection devicemSubtracting the current i in the pre-fault state[0]And obtaining the product.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201811130061.4A CN109193584B (en) | 2016-11-14 | 2016-11-14 | A kind of current protection method of the power distribution network containing distributed photovoltaic power |
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201610997679.5A CN106786413B (en) | 2016-11-14 | 2016-11-14 | The current protection method of the power distribution network containing distributed photovoltaic power |
| CN201811130061.4A CN109193584B (en) | 2016-11-14 | 2016-11-14 | A kind of current protection method of the power distribution network containing distributed photovoltaic power |
Related Parent Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201610997679.5A Division CN106786413B (en) | 2016-11-14 | 2016-11-14 | The current protection method of the power distribution network containing distributed photovoltaic power |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN109193584A CN109193584A (en) | 2019-01-11 |
| CN109193584B true CN109193584B (en) | 2019-11-05 |
Family
ID=58973402
Family Applications (2)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201610997679.5A Active CN106786413B (en) | 2016-11-14 | 2016-11-14 | The current protection method of the power distribution network containing distributed photovoltaic power |
| CN201811130061.4A Active CN109193584B (en) | 2016-11-14 | 2016-11-14 | A kind of current protection method of the power distribution network containing distributed photovoltaic power |
Family Applications Before (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201610997679.5A Active CN106786413B (en) | 2016-11-14 | 2016-11-14 | The current protection method of the power distribution network containing distributed photovoltaic power |
Country Status (1)
| Country | Link |
|---|---|
| CN (2) | CN106786413B (en) |
Families Citing this family (11)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN107453337A (en) * | 2017-09-04 | 2017-12-08 | 湖南长高思瑞自动化有限公司 | A kind of distributed photovoltaic and network protection method and device |
| CN107919646B (en) * | 2017-10-19 | 2019-04-26 | 广东电网有限责任公司电力科学研究院 | A kind of the current protection setting method and device of the power distribution network containing photovoltaic |
| CN107607822B (en) * | 2017-10-27 | 2019-08-27 | 南方电网科学研究院有限责任公司 | System and method for testing self-adaptive current protection performance of power distribution network |
| CN108933438B (en) * | 2018-06-29 | 2021-10-08 | 河海大学 | Distribution network distributed power supply online control device and method based on system operation mode |
| CN109286202B (en) * | 2018-07-28 | 2020-05-22 | 国网江苏省电力有限公司电力科学研究院 | Large-scale inversion type power supply grid-connected tie line current differential protection method, device and system |
| CN109361200B (en) * | 2018-11-26 | 2020-09-01 | 广东电网有限责任公司 | Fault fast switching positioning method and related device and fault isolation system |
| CN110165637B8 (en) * | 2019-03-08 | 2024-07-16 | 中国电力科学研究院有限公司 | Line protection method, system and device for reverse power supply access |
| CN110416981B (en) * | 2019-07-31 | 2020-07-31 | 华北电力大学 | Electric automobile access distribution network area current protection method and system |
| CN110649581A (en) * | 2019-10-30 | 2020-01-03 | 中国南方电网有限责任公司 | Protection method for closed-loop power distribution network containing distributed power supply |
| CN112255567B (en) * | 2020-10-16 | 2023-05-09 | 西安石油大学 | Short-circuit current rapid determination method for power distribution network containing photovoltaic power supply |
| CN113708352A (en) * | 2021-08-23 | 2021-11-26 | 广东电网有限责任公司 | Relay protection method and device |
Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103872665A (en) * | 2014-03-26 | 2014-06-18 | 国家电网公司 | Power distribution network integrated protection method suitable for access of distributed power supplies |
| CN104242273A (en) * | 2014-09-24 | 2014-12-24 | 天津大学 | Self-adaptation positive sequence current quick breaking protection method for power grid containing inverter-based DG (distributed generation) |
| CN104779591A (en) * | 2015-03-30 | 2015-07-15 | 天津大学 | Longitudinal differential protection scheme for inverter interfaced distributed generator teed line |
| CN105098741A (en) * | 2014-05-07 | 2015-11-25 | 国家电网公司 | Relay protection configuration method of distribution network to which distributed generation gets access |
| CN106058830A (en) * | 2016-07-26 | 2016-10-26 | 华北电力大学 | Current protection system with DG power distribution network and protection method |
Family Cites Families (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101552461B (en) * | 2009-01-09 | 2011-01-19 | 天津大学 | Method for protecting power distribution network containing distributed generation |
| CN101515715B (en) * | 2009-04-03 | 2010-09-29 | 天津大学 | WAN-based method for protecting feeder line containing distributed power |
| CN103812095A (en) * | 2014-02-27 | 2014-05-21 | 国家电网公司 | Directional pilot protection method for power distribution network containing distributed generation |
| CN104852362A (en) * | 2015-04-20 | 2015-08-19 | 平高集团有限公司 | Overcurrent protection method and grid structure applicable to power distribution network with distributed generation (DG) |
| CN104810809A (en) * | 2015-04-21 | 2015-07-29 | 国家电网公司 | Micro-grid current selective tripping protection method applicable to photovoltaic multipoint access |
-
2016
- 2016-11-14 CN CN201610997679.5A patent/CN106786413B/en active Active
- 2016-11-14 CN CN201811130061.4A patent/CN109193584B/en active Active
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103872665A (en) * | 2014-03-26 | 2014-06-18 | 国家电网公司 | Power distribution network integrated protection method suitable for access of distributed power supplies |
| CN105098741A (en) * | 2014-05-07 | 2015-11-25 | 国家电网公司 | Relay protection configuration method of distribution network to which distributed generation gets access |
| CN104242273A (en) * | 2014-09-24 | 2014-12-24 | 天津大学 | Self-adaptation positive sequence current quick breaking protection method for power grid containing inverter-based DG (distributed generation) |
| CN104779591A (en) * | 2015-03-30 | 2015-07-15 | 天津大学 | Longitudinal differential protection scheme for inverter interfaced distributed generator teed line |
| CN106058830A (en) * | 2016-07-26 | 2016-10-26 | 华北电力大学 | Current protection system with DG power distribution network and protection method |
Also Published As
| Publication number | Publication date |
|---|---|
| CN109193584A (en) | 2019-01-11 |
| CN106786413B (en) | 2018-10-30 |
| CN106786413A (en) | 2017-05-31 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN109193584B (en) | A kind of current protection method of the power distribution network containing distributed photovoltaic power | |
| Telukunta et al. | Protection challenges under bulk penetration of renewable energy resources in power systems: A review | |
| Lagos et al. | Microgrid protection against internal faults: Challenges in islanded and interconnected operation | |
| Aghdam et al. | Variable tripping time differential protection for microgrids considering DG stability | |
| Hooshyar et al. | Microgrid protection | |
| Nikkhajoei et al. | Microgrid fault protection based on symmetrical and differential current components | |
| Che et al. | Adaptive protection system for microgrids: Protection practices of a functional microgrid system | |
| CN105811382B (en) | The positive sequence impedance differential protecting method of power distribution network containing IBDG of band brake characteristic | |
| Chen et al. | Addressing protection challenges associated with Type 3 and Type 4 wind turbine generators | |
| Kundu et al. | Enhanced protection security using the system integrity protection scheme (SIPS) | |
| Nsaif et al. | Fault detection and protection schemes for distributed generation integrated to distribution network: Challenges and suggestions | |
| Dang et al. | An adaptive protection method for the inverter dominated microgrid | |
| CN106684834B (en) | A kind of power distribution network adaptive Current Protection system and method | |
| Bui et al. | Investigation on transient behaviours of a uni-grounded low-voltage AC microgrid and evaluation on its available fault protection methods: Review and proposals | |
| CN107591785A (en) | Suitable for the distance protecting method and system of the grid-connected network system in new energy station | |
| Kim et al. | LSTM-based fault direction estimation and protection coordination for networked distribution system | |
| Fayazi et al. | An offline three-level protection coordination scheme for distribution systems considering transient stability of synchronous distributed generation | |
| Jalilian et al. | Distance protection of transmission lines in presence of inverter-based resources: A new earth fault detection scheme during asymmetrical power swings | |
| Xu et al. | Positive sequence differential impedance protection for distribution network with IBDGs | |
| Liu et al. | A simple multi agent system based adaptive relay setting strategy for distribution system with wind generation integration | |
| Saleh et al. | Synthetic harmonic distance relaying for inverter-based islanded microgrids | |
| Aziz et al. | Transmission lines differential protection based on the energy conservation law | |
| Ciontea et al. | Decentralized adaptive overcurrent protection for medium voltage maritime power systems | |
| Albasri et al. | Mitigation of adverse effects of midpoint shunt-FACTS compensated transmission lines on distance protection schemes | |
| CN112803376A (en) | Power distribution network protection coordination method after grid connection of photovoltaic power supply |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |